Noncorrosive solutions



Patented June 23, 1931 UNITED STATES PATENT OFFICE WILLIAM S. CALGOTT, F PENNS GROVE, NEW JERSEY, AND HERBERT W. WALKER, OE WILMINGTON, DELAWARE, 'ASSIGNORS TO E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE 1T0 Drawing.

NONCORROSIVE SOLUTIONS I This invention relates to the preparation of aqueous solutions and aqueous alcohol solutions which are substantially inert with respect to iron.

It is well known that water and water solutions of alcohols attack metallic iron in the form of the free metal, cast ironand steel very rapidly under ordinary conditions and considerable corrosion as manifested by rust spots, pitting, deposits and sediment takes place. This is particularly true in the cooling systems of internal combustion engines such as automobile engines, since the metallic container issubjected to alternate hot and cold solutions.

Our invention has for one of its objects the preparation of aqueous and aqueous alcohol solutions which are substantially inert to iron, and which do not corrode or form deposits in the cooling systems of internal combustion engines. Other objects-will be apparent as this description proceeds.

We have found if a small quantity of an amino carboxylic acid or a water soluble derivative of such an acid is added to water or to a water alcohol solution, there results a solution in which the rate of corrosion or iron is decreased to a very marked extent.

' The general formula of the class of compounds falling within the contemplation of our invention is have tested and found to be operative, are

phenyl glycine, anthranilic acid, sodium and potassium salts of phenyl glycine, sodium and potassium salts of anthranilic acid, organic derivatives of phenyl glycine and an- Application filed September 7, 1929. Serial No. 391,106.

thranilic acid, such as the ethanol amine salt of phenyl glycine and the ethanol amine salt of anthranilic acid. The amino acids and their derivatives may be present singly or in mixtures. the amino acids formed from casein in milk containing glycine, alanine, valine, tryptophane, tyrosin, crystine, etc.

By Way of illustration of our invention, the following examples are offered:

Ewample 1 If the sodium salt of phenyl glycine or of anthranili c acid is added to Water or to a E mample 2 If an alkali metal salt, such as the sodium or potassium salt of phenyl glycine or of anthranilic acid, is added in sufficient quantity to make a 1% solution, that is, 1% of the inhibitor and 99% of solvent, to a 40% solution of denatured ethyl alcohol and water or of glycerine and Water or of alcohol and glycerine and water, there is thereby formed a solution which is substantially inert with respect to iron even at elevated temperatures. Glycol may be used in place of either alcohol or glycerine in the above solution.

Since the examples given above are pure ly illustrations, We do not wish to be restricted to the specific amino carboxylic acid or specific solvents or quantities given therein. Any of the Water soluble amino carboxylic acids, their metallic salts, or their water soluble organic salts fall within the broad class of compounds contemplated by our invention. Other derivatives than those mentioned above may be employed such as,

lVe have used a mixture of for example, naphthyl glycine or tolyl glycine or their metallic salts.

Ve do not Wish to be limited to the specific solvents mentioned in our description. The solvents falling within the general formula R (OH) where R may be hydrogen or an alkyl radical and n is an integral number of the value of l or more, may be successfully treated with the amino carboxylic acids or their derivatives. Thus, within the general formula for our solvents we contemplate water and water and mono-hydric alcohols, water and polyhydric alcohols, and even tertiary mixtures of monoand polyhydric alcohols in water. Where in our specification and claims we have used alcohol or watenalcohol without further definition it is to be understood that we mean such alcohols both mono-hydric and polyhydric, both singly and in mixture, which are normally used as anti-freeze ingredients.

The inhibitor may be added to water or to more or less pure mono-hydric alcohol or polyhydric alcohol, and the latter may then be diluted by water with any desired concentration. It is not necessarily required that the solution take place in an undiluted alcohol or in more or less pure water, for the inhibitor may be added to an aqueous alcohol solution of any given concentration. In any event, a distinct protective action on iron is observed in water and monoand pol hydric alcohol solutions when treated wit amino carboxylic acids, their hydrocarbon derivatives, or water soluble salts.

Solutions containing one or more of the compounds falling within our class of inhibitors afford obvious advantages over untreated solutions. When used in internal combustion engine cooling systems there is a marked absence of sediment and rust not only under normal weather conditions, in which water alone is used, but also in freezing weather when anti-freezing soluzions are employed. Our inhibitors find ;uccessful use in protecting storage tanks, lrums or cans for alcohol, glycol or glycerne or other mono-hydric or polyhydric alcolS or their aqueous solutions from :orrosion.

As many apparently widely different em- )odiments of this invention may be made vithout departing from the spirit thereof, t is to be understood that we do not limit 'urselves to the foregoing examples or decriptions except as indicated in the followug patent claims.

We claim:

1. A composition of matter, which when dded to water and water-alcohol mixtures enders said liquids substantially non-corroive toward ferrous materials, comprising at :ast one substance from the group of ydroxyl-containing compounds consisting f moro-hydric alcohols and polyhydric alcohols together with a small amount of a compoud of the type in which R and R may be alkyl, aralkyl or aryl nuclei, 3 may be an alkyl, aralkyl or aryl group or nothing, and R is hydrogen, a metal capable of forming a water soluble salt or an organic base capable of forming a Water soluble salt.

2. A composition of matter, which when added to water and water-alcohol mixtures renders said liquids substantially non-corrosive toward ferrous materials, least one substance from the group of hydroxyl-containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of a water soluble derivative of an amino carboxylic acid.

3. A composition of matter, which when added to Water and Water-alcohol mixtures renders said liquids substantially non-corrosive toward ferrous materials, comprising at least one substance from the group of hydroxyl-containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of an alkali metal salt of an amino carbozylic acid.

4. A composition of matter, which when added to Water and water-alcohol mixtures renders said liquids substantially non-corrosive toward ferrous materials, comprising at least one substance from the grou of hydroxyl-containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of an alkali metal salt of phenyl glycine.

5. A composition of matter, which when added to water and water-alcohol mixtures renders said liquids substantially non-corrosive toward ferrous materials, comprising at least one substance from the group of hydroxyl-containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of the sodium salt of phenyl glycine.

6. A composition of matter which when added to water and water-alcohol mixtures renders said liquid substantially non-corrosive toward ferrous materials comprising at least one substance from the group of hydroxyl'containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of a water soluble salt of phenyl glycine.

7. A composition of matter, which when added to water and water-alcohol mixtures renders said liquid substantially non-corrosive toward ferrous materials, comprising at least one substance from the group of hydroxyl containin compounds consisting of mono-hydric alco hols and polyhydric alcocomprising at hols together with a small amount of an I ethanolaminesalt of phenyl glycine.

8. A composition of matter, which when added to water and water-alcohol mixtures renders said liquid substantially non-corrosive toward ferrous materials, comprising at least one substance from the group of hydroxyl containing compounds consisting of mono-hydric alcohols and polyhydric alcohols together with a small amount of a water soluble amino carboxylic acid derivative of the group consisting of phenyl glycine, anthranili'c acid, the sodium salt of phenyl glycine, the sodium salt of anthranilic acid, the potassium salt of phenyl glycine, the potassium salt anthranilic acid, the ethanolamine salt of phenyl glycine, the ethanolamine salt of anthranilic acid, naphthyl'gl cine, tolyl glycine, the alkali metal salts o naphthyl glycine and alkali metal salts of tolyl glycine.

9. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metalv in the presence of a smallamount of a compound of the type Rl-N-Rr-COORL in which R and R may be alkyl, aralkyl or aryl nuclei, R may be an alkyl, aralkyl or aryl group or nothing, and R is hydrogen, a metal capable of forming a water soluble salt or an organic base capable of forming a water soluble salt.

10. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comsion of an. oxidizable metal upon contact with Water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metal in the presence of a small amount of the sodium salt of phenyl glycine.

15. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metal in the presence of a small amount of an ethanolamine salt of phenyl glycine. I

16. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metal in the resence of a small amount of a soluble ammo carboxylic acid derivative of the group consisting of phenyl glycine, anthranilic acid, the sodium salt of phenyl glycine, the sodium salt of anthranilic acid, the potassium salt of phenyl glycine, the potassium salt of anthranilic acid, the ethanolamine salt of phenyl lycine, the ethanolamine salt of anthranihc acid, naphthyl glycine, tolyl glycine, the alkali metal salts of naphthyl glycine and alkali metal salts of tolyl glycine.

In testimony whereof we afiix our sigma-- tures.

WILLIAM S. CALCOTT. HERBERT W. WALKER.

prises contacting said liquids with the oxidizable metal in the presence of a small amount of a water soluble derivative of an amino carboxylic acid.

11. The process of inhibiting the corro-. sion of an oxidizable metal upon contact with water or water-alcohol mixtures which com risescontacting said liquids with the oxi izable metal in the presence of a small amount of an alkali metal salt of an amino carboxylic acid.

12. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metal in the presence of a small amount of a water soluble salt of phenyl glycine.

13. The process of inhibiting the corrosion of an oxidizable metal upon contact with water or water-alcohol mixtures which comprises contacting said liquids with the oxidizable metal in the presence of a small amount of an alkali metal salt of phenyl glycine.

14. The process of inhibiting the corro- I'IO 

